CONTROL OF BOLL WEEVIL IN MISSISSIPPI DELTA. 



25 



abundant to allow square-infestation records. This type of record 

 was begun on June 15 and continued at weekly intervals until 

 August 9. At the first three examinations 100 squares were examined 

 in each corner and the center of each plat, making a total of 500 

 squares to the plat. Beginning with July 4, however, the records 

 were made in the center of each end and the middle of each plat, 

 200 squares being examined at each point, making a total of 600 

 squares to the plat. 



Table 22 shows the figures secured at these examinations. 



Table 22. — Weevil infestation, Hecla plantation experiment. Mound, La., 1916. 



Date of examination. 



June 15 



June 20 



June 27 



July 4 



July 10 



July 17 



July 26 



Aug. 1 



Aug.9 



Weighted averages 



Infestation. 



Picked 

 plat. 



Per cent. 

 65.6 

 43.8 

 34.0 

 39.0 

 25.7 

 47.0 

 48.2 

 71.0 

 87.8 



51.5 



Check 

 plat. 



Per cent. 

 49.0 

 47.8 

 38.6 

 25.5 

 24.7 

 50.2 

 53.2 

 67.8 

 89.8 



49.9 



From Table 22 it is seen that there was no significant regularity 

 in the comparative infestation of the two plats. In fact, in the 

 weighted average for the season there was a difference of only 1.6 per 

 cent in the infestation of the two plats. These infestation records 

 failed to show any effect whatever from the pickings, as there was no 

 apparent reduction in the infestation of the picked plat at any time. 



Averages of the infestation records at each of the points of observa- 

 tion throughout the season give the following: 



Picked plat: Percent. 



West end 54. 4 



Center 47. 4 



East end - 52. 1 



Check plat: 



West end 49. 4 



Center > 50. 8 



East end 49. 2 



From these averages it is seen that the infestation was very evenly 

 distributed over the two plats, as the extreme range was only from 

 47.4 per cent to 54.4 per cent. It is interesting to note that both of 

 these extremes were located in the picked plat. The averages at the 

 points where the infestation was determined are further evidence of 

 the failure of the picking operation to reduce the weevil infestation 

 in the picked plat. 



96828°— Bull. 564—17 4 



